Spark-plug.



A. SCHMIDT.

SPARK PLUG.

APPLICATION mu) JAN-H, 1917.

1,230,796. Patented June 19, 1917.

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as shown..

C aml 1s prom hon L Whl JLOiL ea beet yond tins head portion M LE LL, "3, AfiQIGH C Sgecl sw time 02 Letters Application file (mcem: e A: known that I, ALBERT Sam/1m 2a 1c of Faramce resuhng unty of Genesee and State ichlgan, have invented cermm new and useful improvements 1n Spark-Plum, Whmh the followmg 1s a specmca'tlon, refer eemfimm =01? L23fifi To all whom it may 0 B citizen of the Republ at Mint, in the co v? of M er ami hofi- 75 ti er end is the mefizallie casing Fi a A A w n U L Had L v/ E 1 AYE G 8 m a u 0.? 0 ?H S 2w v 6 PM d V Mme 6 21 a "ma um V f h u mem n w w w 1 n .SKA 5 2 r: DU

7 sfaser .e

member tame mem- .1e ei means emem;

diameter so as to her I and the conical head L is restricted in pass through the insulator H.

What I claim as my invention is:

1. In a spark-plug, the combination with the outer casing, of an insulator mechanically secured and sealed within said outer casing, an electrode mechanically supported and sealed in said insulator, a second insulator independent of said first-mentioned insulator, extending inward therefrom and surrounding the exposed end of the electrode, and a metallic member intermediate said insulators, being protected from heat by the inner insulator and forming a means for dissipating the heat from the electrode.

2. In a spark-plug, the combination with a metallic casing, of an insulator mechanically secured and sealed therein, a tubular insulator extending inward from said firstmentioned insulator and independently secured within said casing, an insulator sleeve surrounding both of said insulators and overlapping the joint therebetween, a metallic member intermediate said outer and inner insulators an electrode seated upon said metallic member, extending outward through the outer insulator and mechanically secured thereto, the inner end of said electrode extending through said inner insulator, said electrode normally dissipating its heat through said metallic member and being removable therefrom through said inner insulator.

3. in a spark-plug, the combination with an outer casing, of an insulator mechanitally secured and sealed therein, a tubular insulator extending inward from said firstmentioned insulator and independently secured within said casing, an insulator sleeve surrounding the outer and inner insulators, bridging and overlapping the gap therebetween, a metallic head in the space between the outer and inner insulators and provided with a tapering seat, and an electrode having a head portion for engagement with said tapering seat and a shank portion passing outward through said outer insulator,

the inner end of said electrode extending.

through said inner insulator and the whole electrode being removable through said inner insulator.

4:. A spark-plug, comprising a metallic casing, an insulator mechanically secured and sealed in said casing and terminating short of the inner end thereof, a metallic member at the inner end of said insulator, an electrode seated on said metallic member and passing through said insulator, a tubular insulator member surrounding the inner end of said electrode and protecting said metallic member, said tubular insulator being independently secured within said casing, being highly refractory to the heat of the explosion chamber, and an insulator sleeve surrounding and overlapping the gap between the outer and inner insulators and increasing the electrical insulation of the latter, being protected from the high heat thereby,

In testimony whereof I aiiix my signature.

ALBERT SCHMIDT. 

